distribute_setup.py 文件源码

def use_setuptools(version=DEFAULT_VERSION, download_base=DEFAULT_URL,
                   to_dir=os.curdir, download_delay=15, no_fake=True):
    # making sure we use the absolute path
    to_dir = os.path.abspath(to_dir)
    was_imported = 'pkg_resources' in sys.modules or \
        'setuptools' in sys.modules
    try:
        try:
            import pkg_resources
            if not hasattr(pkg_resources, '_distribute'):
                if not no_fake:
                    _fake_setuptools()
                raise ImportError
        except ImportError:
            return _do_download(version, download_base, to_dir, download_delay)
        try:
            pkg_resources.require("distribute>="+version)
            return
        except pkg_resources.VersionConflict:
            e = sys.exc_info()[1]
            if was_imported:
                sys.stderr.write(
                "The required version of distribute (>=%s) is not available,\n"
                "and can't be installed while this script is running. Please\n"
                "install a more recent version first, using\n"
                "'easy_install -U distribute'."
                "\n\n(Currently using %r)\n" % (version, e.args[0]))
                sys.exit(2)
            else:
                del pkg_resources, sys.modules['pkg_resources']    # reload ok
                return _do_download(version, download_base, to_dir,
                                    download_delay)
        except pkg_resources.DistributionNotFound:
            return _do_download(version, download_base, to_dir,
                                download_delay)
    finally:
        if not no_fake:
            _create_fake_setuptools_pkg_info(to_dir)